Bash: "expr index string1 string2" gives "syntax error"

Question

In a bash script, I was trying to use the command
expr index string1 string2
to find the position of string2 in string1, but this does not work on OS X while it works ok on several Linux machines. Reading the man page, I realized expr does something quite different on OS X than on Linux.
Can anybody suggest which command I should use to get the same functionality of the above on OS X?
Thanks
Andreas

Answer 1

Hi Ken,
   Wow! That's something you don't see every day; I'm really impressed. I had had a tough day too. Later I thought of a funny answer in which I blamed everything on the crazy shell I use. The difference between the two answers is just the flow of karma but stopping the flow of negative by saying something is a real and difficult choice and yours shows character. I'm sorry for going on too much but such things matter more than machines.
   On the other hand, you're a royal pain in the ... just kidding. You're a strict task master but right; I read in the man page about it returning zero and forgot. However, mathematically it isn't too difficult; you just have to use modular arithmetic. In zsh, (I can learn) it would look like:
test=aabbcc
echo $(( ( ${#test%%[bc]*} + 1 )%( ${#test} + 1 ) ))
In bash, it would look like:
test=aabbcc
testtmp=${test%%[bc]*}
echo $(( ( ${#testtmp} + 1 )%( ${#test} + 1 ) ))
Gary
~~~~
   In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
         -- Carl Sagan, 1987 CSICOP keynote address